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| author |   Kuan-Wei Chiu <visitorckw@gmail.com> | 2024-09-28 19:36:08 +0800 |
|---|---|---|
| committer |   Petr Mladek <pmladek@suse.com> | 2024-12-12 10:10:03 +0100 |
| commit | 3d6f83df8ff2d5de84b50377e4f0d45e25311c7a (patch) | |
| tree | e64f31472ec3d6346a44e471aa7f2def8c4328e2 | |
| parent | Merge tag 'printk-for-6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux (diff) | |
| download | linux-rng-3d6f83df8ff2d5de84b50377e4f0d45e25311c7a.tar.xz linux-rng-3d6f83df8ff2d5de84b50377e4f0d45e25311c7a.zip | |
printk: Fix signed integer overflow when defining LOG_BUF_LEN_MAX
Shifting 1 << 31 on a 32-bit int causes signed integer overflow, which
leads to undefined behavior. To prevent this, cast 1 to u32 before
performing the shift, ensuring well-defined behavior.
This change explicitly avoids any potential overflow by ensuring that
the shift occurs on an unsigned 32-bit integer.
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Acked-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240928113608.1438087-1-visitorckw@gmail.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
| -rw-r--r-- | kernel/printk/printk.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 80910bc3470c..d8d82dd39dee 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -523,7 +523,7 @@ static struct latched_seq clear_seq = { /* record buffer */ #define LOG_ALIGN __alignof__(unsigned long) #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) -#define LOG_BUF_LEN_MAX (u32)(1 << 31) +#define LOG_BUF_LEN_MAX ((u32)1 << 31) static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); static char *log_buf = __log_buf; static u32 log_buf_len = __LOG_BUF_LEN; |